The present invention relates to the field of cellular wireless communications, and more particularly, to a method of controlling the transmission of identities associated with a wireless communications device to a wireless communications network.
In order for a wireless communications network to check whether a particular service subscription is valid, or to cross-reference other relevant data, the network must be able to identify the subscription. Typically this is done by having the wireless communications device provide a unique identifier to the network when requesting service. For instance, in a traditional ANSI-41/ANSI-136 network, a cellular phone transmits its Electronic Serial Number (ESN) when the phone performs any one of a variety of wireless communications control functions, such as registration or call origination. The control of this identity transmission in ANSI-41/ANSI-136 is based upon a broadcast control bit, known as the xe2x80x9cSxe2x80x9d bit, that the network may selectively turn on or turn off. When the S-bit is turned on, the wireless communications devices directly interacting with the network are required to transmit the identity when performing any of the wireless communications control functions known generally as registration, origination, page response, base station challenge order, R-data (teleservices), and SPACH confirmation.
Further, it is possible that wireless communications devices will have more than one identity. Traditionally, a wireless communications device had one unique fixed identity in ANSI-41/ANSI-136 networks. In the ANSI-136 nomenclature, this was the ESN. The wireless communications device was manufactured with this ESN, which under FCC regulations cannot be altered after manufacture. The traditional ANSI-41/ANSI-136 service subscription was then tied to a particular wireless communications device, typically by including the ESN as part of the subscription information uplinked to identify the subscription to the network. Thus, the traditional ANSI-41/ANSI-136 subscriber could not use a different piece of equipment, such as another user""s phone handset, for the same subscription.
The situation with traditional ANSI-41/ANSI-136 is to be contrasted with that under the standard known as Global System for Mobile Communication (GSM). In the GSM world, a wireless communications device has two functional parts, a subscription module and a mobile terminal. The subscription module, commonly known as either the Subscriber Identity Module (SIM), the SIM card, or a User Identity Module (UIM), may be thought of as an electronic identification card; it contains the subscription-related information required to verify the subscriber to the network. The SIM card typically includes memory and other electronics for performing a variety of functions, but the SIM card does not include the transceiver electronics necessary for the main GSM wireless communications. For reference, see GSM 11.11 and GSM 11.14 for SIM card specifications in the GSM network. Relevant to the present discussion, the SIM card contains a fixed subscription identifier, similar to that of the ESN of ANSI-136. For ease of reference, this identifier will be referred to as the ESNs.
The GSM mobile terminal is the rest of the wireless communications device without the subscription module. Thus, the mobile terminal is the handset or other main unit that includes the main GSM transceiver circuits, the speaker, etc. The mobile terminal likewise includes a fixed identifier, which is referred to as the International Mobile Equipment Identifier (IMEI), or the ESNm.
The GSM subscription module is inserted or otherwise connected to the GSM mobile terminal to form a complete wireless communications device that is useable in GSM. The subscription information is read from the subscription module by the mobile terminal and transmitted to the network where the network determines whether the subscription is valid and registers the location of the subscription within the network. Thus, the GSM service subscription is typically not tied to a specific mobile terminal, but rather is tied to the subscription module. Because the subscription module authenticates the user to the network, the user is free to use any compliant mobile terminal equipment by simply mating their subscription module to the mobile terminal and repeating the authentication and registration process with the new mobile terminal hardware. Thus, it is not always necessary for the user to carry the complete wireless communications device in order to access his/her wireless service subscription. Instead, the user need only carry the subscription module and mate the module to an appropriate mobile terminal available on-location.
It should be noted that there is a provision in GSM for the network to request that the wireless communications device send the ESNm of the mobile terminal, typically for purposes of tracking lost or malfunctioning mobile terminals. The process for this in GSM is for the GSM network to make point-to-point contact with a particular wireless communications device and request that particular wireless communications device to send its ESNm.
The idea of allowing the use of small, inexpensive subscription modules, similar to SIM cards, is gaining favor in the ANSI-41/ANSI-136 world due to the desire for subscription mobility. However, traditional ANSI-41/ANSI-136 contemplates the existence of only one fixed identity per wireless communications device, not two or more. Quite simply, ANSI-41/ANSI-136 anticipates that the equivalent to the subscription module will always be mated to the same mobile terminal, and will not be portable between mobile terminals, therefore only one fixed identity is required per wireless communications device. Because newer subscription-module-enabled wireless communications devices will have two (or more) fixed identities, ANSI-41/ANSI-136 networks may need to be modified to accommodate the presence of more than one fixed identifier associated with a wireless communications device. For instance, a particular network entity, such as the Authentication Center, may need the identity of the subscription module for some control functions and the identity of the mobile terminal for others. Thus, there is a need for an improved ANSI-41/ANSI-136 protocol that accommodates the presence of more than one fixed identifier associated with a wireless communications device. Such a method should preferably allow the network entity to be provided with one type of wireless communications device identity during some control functions, and another type of identity during other control functions.
From the above, it is clear that there remains a need for an improved method of controlling the provision of wireless communications device identities to various entities within the wireless communications networks.
The present invention determines which of two or more identifiers belonging to the wireless communications device should be provided to the network entity based upon the control function being processed, or more generally, upon the class of control function being processed. In one embodiment, a Mobile Switching Center (MSC) receives a plurality of identifiers and a control function request from a wireless communications device. The MSC determines which of the identifiers are needed by the network entity to process the requested control function based on the control function requested. The MSC filters the received identifiers to remove unneeded identifiers based on its analysis and forwards the filtered identifiers to the network entity and/or to another network.
In another embodiment, the present invention pushes the determination of which identifier to send downward to the wireless communications device itself. In these embodiments, the wireless communications device is programmed to determine which identifier is needed, and this identifier is transmitted to the MSC with the control function message. This determination by the wireless communications device of which identifier is needed is independent of the network, not simply a response to a command from the network. While the network may signal to the wireless communications device whether or not to send an identifier, it is the wireless communications device that determines which of a plurality of identifiers to send.
The present method may be used to help insure that the proper identity is sent by the MSC to other network entities when the wireless communications device includes more than one fixed identifier. The method is particularly adapted for situations where the wireless communications device includes a subscription module having a subscription module identifier and mobile terminal having a mobile terminal identifier.